Bottle dropper and closure



June 2, 1964 G. BALLIN BOTTLE DROPPER AND CLOSURE f f l f z f Filed Deo.25, 1959 June 2, 1964 G, BALLlN BOTTLE DROPPER AND cLosURE 3Sheets-Sheet 3 Filed Dec. 23, 1959 3 M ou ww a www United States PatentO 3,135,302 BOTTLE DROPPER AND CLOSURE Gene Ballin, Valley Stream, N.Y., assignor to Dosamatie This invention relates to droppers forliquids, and more particularly to` a combined bottle closure and droppersuitable for use in dispensing medicaments, reagents and otherpreparations of a type administered or measured out drop by drop or inother small measured amounts.

Conventional liquid droppers are provided with a resilient, rubber-likebulb fitted upon the upper end of a glass dropper tube or pipette. Uponsqueezing the bulb, a portion of the air therein is forced out and, uponreleasing the bulb or relaxing the force on it, the liquid to bedispensed is drawn into the lower end of the tube and may thereafter bedispensed by again squeezing the bulb. In the packaging and use of suchdroppers, an important problem has been the possibility of chemicalinteraction between the material of the bulb and the liquid beingdispensed. If a rubber bulb dropper is used with a liquid having an oilbase, care has to be taken to be certain thatthe liquid does not contactthe bulb, since the rubber part deteriorates very rapidly in contactwith oil. Also, many medicinal preparations and reagents are delicatelybalanced and unstable, andundergo definite chemical changes on contactwith air or rubber, not only causing a deterioration and discolorationof the preparation, but also having an adverse effect on the bulbmaterial.

Since in the conventional dropper, the pipette directly communicateswith the bulb, attempts have been made to restrict this communication inorder to prevent the liquid from contacting the rubber bulb. However,these attempts have not been satisfactorily successful in preventingleakage of the liquid or fluid into the bulb during use, particularlywhen the dropper is inverted or even placed on a horizontal surface. i

In addition, in packaging medicaments or the like in `bottles withdropper dispensers, these factors have introduced undesirablecomplexities and costs.

One of the requirements for shipping medicaments and like liquids inbottles is that the bottle or containing vessel be completely andtightly sealed; this seal must be fully positive and effective, and, indistinction to the normal closure of the vessel between uses (for whichthe requirements are less stringent), is known as a primary seal. Tomaintain a primary seal and to avoid contact between the liquid in thebottle-and the dropper bulb during shipment or shelf storage, it hasbecome customary to utilize a separate primary seal cap closure 4for thebottle, and to provide a separate dropper in the same package. This, ofcourse, is bulky and costly to package and awkward to use, since in usethe cap must rst be removed, the dropper inserted andutilized, and thenthe cap must be replaced and the separate dropper then becomes awkwardto store, since it is generally still wet from the liquid dispensed. Inaddition, sanitary problems are created as well as creating thepossibility of misplacing the dropper and not having it available whenneeded. In an attempt to overcome these problems, the dropper has beenprovided with a cap structure, so that the purchaser `first removes theprimary seal cap used in shipment, and substitutes adropper-caprpackaged together with but independent from the cappedbottle. Thereafter the same problem exists of deterioration between bulbmaterial and the liquid to be. dispensed. In this arrangement theprimary seal has been separate from the dropper-cap, and no satisfactoryarrangement has been thus far devised for avoiding the necessity of sucha sep- -arate primary seal.

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According to the present invention, a dropper and cap arrangement isprovidedwhich creates a primary seal for the bottle and also isolatesthe pipette from the bulb to avoid deterioration of the containedliquid.

It is a primary object of the present invention to provide a dropperclosure which incorporates a primary seal suitable for producing aleakproof closure for the-container suitable both for ordinary storageand for withstanding the vicissitudes of shipment and handling beforereceipt by the ultimate user.

It is another object of the present invention to provide a liquiddropper closure construction which eliminates communication between thepipette and the lbulb of the dropper when the dropper is tightened onthe container, and automatically restores that communication when thedropper is loosened preparatory to use.

Still another object of the present invention is to provide a liquiddropper assembly wherein the dropper provides a cap for a container forthe liquid to be dispensed, thus eliminating a separate sealing cap, forall types of preparations.

Prior art droppers have also been extremely unreliable in dispensingmedicament or other preparations with accuracy. With the ordinary,elongated rubber bulb, the mechanical force required to compress thebulb for ejecting .the liquid from the pipette is so small that normallythe force exerted on the bulb is far greater than necessary for ejectingthe-few drops usually needed, and normally the bulb is entirelycollapsed, thus ejecting or aspirating a much larger quantity of thefluid than desired. With certain drugs the excess may even 'be harmful.In an attempt to overcome this danger, pipettes have been often markedor graduated, so as to indicate approximately the number of drops ofliquid which have been drawn into the pipette. However, lthis has notproven satisfactory. Unless the bulb is compressed only enough to drawin the desired amount of liquid, removing the lower-endvof the pipettefrom the liquid after the desired amount of liquid is drawn into thepipette, and allowing the, bulb to returnto its original position,interposes air bubbles in the liquid in the pipette, which is notdesirable.

In another attempt to control the quantity of lluid aspirated from thepipette, the bulb has been made of such a shape as to increase thepressure required to compress the bulb for drawing the liquid into thepipette. Also, bulbs have been made of less pliable material than rubberto increase the force required to compress the bulb so` as to imposeanapproximate control over quantity. However, none of these attempts hasbeen successful in controlling uniformly or accurately, the quantity ofliquid aspirated from the dropper. l

My prior application Serial No. 838,678 for Liquid `Dropper Assembly,led September 8, 1959, now U.S.

Patent No. 3,020,938, discloses and claims a structure which overcomesthis difficulty. The presentl invention, according to another feature,provides improved structures for solving this same problem.

Accordingly, another object of the present invention is to provide aliquid dropper which has quick accurate means for measurement anddispensing of a selected dosage. v

A further object of the present invention is to provide a liquid dropperhaving positive discharge control so as to accurately and repeatedlydetermine the number of drops of liquid which can be drawn into thepipette or be aspirated from the dropper.

A still further object of this invention is to provide an improvedliquid dropper having precise metering and indicating means which areadjustable at` will for controlling the number of drops which areaspirated from the pipette regardless of the pressure exerted upon thebulb.

Another object is to provide a dropper-cap assembly assembly, issanitary and simple in construction and operation, and is durable andconvenient to use.

These and other objects and advantages of the present 'invention will beapparent from the following description of preferred embodimentsthereof, taken with the accompanying drawings, wherein FIGURE 1 is anelevational view, partially broken away, showing the general arrangementof a liquid dropper assembly in accordance with the present invention incombination with a liquid-containing bottle for which the assemblyserves as a closure cap;

FIG.` 2 is an enlarged, fragmentary, cross-sectional elevational Viewtaken alone line 2-2 of FIG. l showing one form of dropper-cap assemblyaccording to one aspect of the present invention, in its closed orsealed position;

FIG. 3 is a cross-sectional View similar to FIG. 2 but showing thedropper-cap assembly unthreaded and separated from the bottle neck;

FIG. 3A is a fragmentary cross-sectional view of a modifiedconstructionshowing an alternative manner of joining the bulb and cappieces of FIGS. 2 and 3;

FIG. 4 is a perspective View in section showing the cap piece of thedropper-cap assembly of FIGS. Zand 3;

FIG. 5 is an elevational view showing another embodiment of a liquiddropper-cap construction for a bottle, providing a primary seal inaccordance with one aspect of the present invention and additionallyproviding dropmetering means in accordance with another aspect of theinvention;

FIG. 6 is an enlarged cross-sectional elevational view taken along lines6-6 of FIG. 5, showing the droppercap in its closed or sealed position;

FIG. 6A is a fragmentary view similar to FIG. 6, but with thedropper-cap assembly loosened on the bottle;

FIG. 7 is a transverse crosssectiona1 view of the structure of FIGS. 6and 7 taken along line 7-7 of FIG. 6;

FIG. 8 is a similar cross-sectional view of the same structure takenalong line 8-8 of FIG. 6; and

FIG. 9 is an exploded, front elevational, cross-sectional view of theembodiment of the dropper assembly of FIGS. 6 to 8, showing the partsthereof in their disassembled n state.

Referring first to the embodiment shown in FIGS. 1 through 4 of thedrawings, numeral 10 generally designates a bottle, vessel or containerwith which one embodiment `of a liquid dropper-cap assembly 11constructed in accordance with the present invention may be used. Bottlemay contain a liquid 12, and is provided with an exteriorly threadedneck or mouth 14. The dropper-V cap assembly llcomprises alongitudinally extending pipette or applicator 18 in the form of a tubehaving a passage 20 formed therein which extends the full length ofpipette 18 and isopen at both ends. As shown in FIG. 1, pipette 18 maybe slightly tapered at its lower end, so that the lower end has asomewhat smaller diameter than its upper end. The upper end of pipette18 has an outwardly and upwardly ared section 22 terminating in a rim24. Rim 24 has a diameter substantially equal to the outer diameter ofthreaded bottleneck 14. Depending downwardly from rim 24 and preferablyintegral or unitary therewith is a skirt portion 28 which issubstantially coaxial with pipette 18. The inner surface of skirt 28 ispreferably provided with threads 3@ adapted to be engaged with thecorresponding threads of neck 14 of bottle 1t). Advantageously the aredupper end material and it has been found convenient to mold the entirepipette and skirt portion 28 integrally from a ilexible syntheticplastic material such as polyethylene. However the lower portion ofpipette 18 may be made of glass or other material and interconnected inairtight relation in any convenient manner with outwardly ared section22. v

Surrounding the outer peripheral surface of skirt portion 28 of pipette18 is a generally cylindrical and preferably integral and generallyrigid cap piece 32 extending upwardly beyond rim 24. Disposed betweenthe ends of cap piece 32 and spaced above the upper surface of rim 24 ofpipette 18 is a transverse wall or disc 34 extending across the interiorof cap 32. Depending from and formed 011 the lower surface of transverseWall 34 is an annular bead or rib 36. The lower surface of rib 36 isspaced from the flared neck portion 22 of pipette 18 when thedropper-cap assembly is loosened or removed from the bottle 11, as shownin FIG. 3. Rib 36 is preferably positioned radially so that it is spacedinwardly from the outer wall 33 of cap piece 32 and overlies the innertop edge of bottle neck 14 as illustratively shown in FIG. 2. About theinner peripheral surface of cap piece 32 and abutting the lowerperipheral edge of disc 34 is a rib 40 which eX- tends downwardly fromdisc 34 substantially the same distance as rib 36 to abut the uppersurface of rim 24 of pipette 18 in the closed position. Cap wall 33 andskirt 28 of pipette 18 are joined together in any suitable manner forforming an airtight seal, such as by heat sealing, cementing, pressedfitting, or the like.

A dome or bulb-shaped piece 44 of a pliable and resilient material, suchas rubber or polyethylene, encloses an air space over disc 34.Advantageously, bulb 44 has 'a comparatively thin, upwardly domed,flexible central portion 46 and a' depending skirt portion 48. The bulbskirt portion 48 is dimensioned to lit tightly against the innerperipheral surface of cap wall 33 above disc 34. The outer surface ofbulb skirt portion 48 is securely joined in any suitable` manner to theinner surface of cap wall 33 to form an air-tight seal. This may be doneby cementing, heat-sealing, pressed fitting, or the like. One convenientY manner of accomplishing this is shown in FIG. 3A. About the outerperipheral surface of bulb skirt portion 48 is an outwardly projectingannular rib or flange 52. The interior peripheral surface of cap wall 33is formed with a cooperating interiorly facing annular groove 54. Groove54 is spaced upwardly from disc 34 and is complementary to rib 52, sothat rib 52 is tightly received in groove 54 upon assembly of bulb 44and cap 32, thus forming an airtight seal. Advantageously, an annularrib 56 extends upwardly from disc 34, spaced from the inner surface ofcap wal133 a distance sufficient to receive skirt portion 48 of bulb 44therebetween. Rim 56 aids in holding the bulb in airtight relation withcap 32 and ensures a dependable seal even upon severe flexing orcontinued usage. Other arrangements for joining bulb 44 to cap 32 mayalso be used, such as having bulb 44 surrounding and sealed to cap 32,as by a rib and groove arrangement similar to that of FIG. 3A.

Disc 34 has a plurality of passages or apertures 60 passing therethroughbetween downwardlyextending rib 36 and flange 40. Thus, bulb 44, cappiece 32 and pipette 18 are joined into a unitary dropper-cap assemblystructure 11, with an air space 45 Within bulb dome 46 communicatingwith the interior 20 of pipette 18 only by way of passages 60. While aplurality of passages are shown, this is illustrative and if desiredonly one may be used, gvith 9further advantages described below relativeto FIGS.

As shown in FIG. 3, rib 36 of disc 34 is normally spaced from the upperflared portion 22 of pipette 18 when the dropper assembly 11 iswithdrawn from bottle 11. As seen best in FIG. 2, upon engaging thethreads 30 on the inner surface of pipette skirt 28 with thecorresponding threads 15 on the neck of bottle 14, and upon tighteningcap 32, disc 34 and the flared portion 22 of pipette 18 are carrieddownwardly toward the upper rim 24 of neck 14 until ared portion 22engages the upper rim 24 to form a tight seal and due to itsyieldability accommodates itself to any slight production variations inshape or dimensions of the bottle neck 14. At the same time, tighteningof cap 32 causes the pipette iiared portion 22 to distort from the shapeshown in FIG. 3 to conform more closely to the upper rim 28 of bottleneck 14, and forces rib 36 into engagement with the upper surface oftapered portion 22 of pipette 18, to form a positive seal therebetween,as shown best in FIG. 2. 'Since air passages 60 in disc 34 are disposedradially outwardly of rib 36, all communication between pipette 18 andthe interior of bulb 44 is terminated. In this condition, as shown inFIG. 2, even if bottle is inverted or shaken, no liquid can escape orenter into the bulb 44. Hence, dropper assembly acts as a positivesealing cap for bottle 10 and provides a primary seal as required duringtransporting or storing bottle 11, with complete isolation of liquid 12from bulb 44.

To use assembly 11 as a dropper, cap 32 is loosened by unthreading itfrom bottle neck 14. When cap 32 has been rotated suiiiciently so thatdownwardly extending rib 36 is no longer in contact with ilared neckportion 22 of pipette 18, pipette passageways 20 once again communicatewith bulb 44. Dome section 46 may then be compressed into a positionsuch as indicated by the dotted lines in FIG. 3. In a manner well knownto the art, this inward pressure forces air from within bulb 44 throughpassageways 60 of disc 34, through pipette passageway 20, and outwardlyof the lower end of pipette 18. On release of center portion 46 of bulb44, the bulb 44 resumes its normal position shown in solid lines, anddue to the reduction in pressure within pipette 18, the desired liquidcharge is drawn into pipette 18. The dropper assembly 11 may then beremoved from the neck 14 of the bottle 10 and used in the usual manner.

While cap 32 and pipette 18 have been indicated as separate pieces, thecap wall 33 and pipette 18 may be made from a single piece constructionwhich can be molded of any suitable material such as any one of the manyavailable, appropriate, synthetic organic resins. In such case, disc 34may be a separate piece suitably secured within cap wall 33. Pipette 18,for example, may be molded of polyethylene, which gives to the flaredportion 22 the ilexibility and resiliency which is highly desirabletforproviding a tight sealing fit upon the mouth of neck portion 14 of thebottle cap without the use of auxiliary washers or gaskets. Also, theouter surface of cap 32 is'preferably roughened or knurled so as toprovide easy gripping for tightening or loosening. Further, if desired,the threaded skirt portion 28 of pipette 18 can be eliminated and aseparate means for clamping the flared neck portion 22 to the rim 'ofbottle 10 may be used. In this embodiment rim 24 would be sealed in someconvenient manner to disc 34, and cap wall 33 may be provided withintegral internal threads to engage threads of bottle 10. j

FIGS. 5 to 9 show a modified form of dropper-cap assembly whichincorporates a primary seal arrangement generally similar to thatalready described,` in combination with liquid-metering means forming afurther feature of this invention. In this form of the presentinvention, by adjusting the relative rotative position of the cap withrespect to the bulb, it is possible to adjust the extent to which thebulb may be depressed for selectively determining the desired amount ofliquid which is drawn into the tube or pipette of the liquid dropperupon release of the bulb to its normal position or for determining theamount of liquid expelled from the pipette upon once more depressing thebulb.

In a manner generally similar to that shown in FIGS. 41-4A, liquiddropper-cap assembly 80 is shown in combination with a bottle 82 whichhas a neck portion 84 with threads 87 thereon. As previously indicated,bottle 82 may contain a liquid to be dispensed by the dropper assembly.Dropper assembly has a cap 85 with a depending skirt portion 86. Theinner surface of skirt 86 is provided with threads 88 which are adaptedto engage with the corresponding threads 87 of bottle neck 84. The outerperipheral surface of skirt 86 is preterably knurled or roughened orprovided with longitudinal ribs, as best seen in FIG. 5, to aid ingripping and rotating the dropper assembly 80 upon bottle neck 84. Cap85 has an upwardly projecting rim 90 which is provided with aninteriorly facing annular bead or rib 94 forming an annular groove 92which has its upper edge peripherally dened by rib 94. At the bottom ofgroove 92 is a transverse structure indicated generally at 96 in FIG. 9,which extends across the inner bore of cap 85 and supports a centralstructure described more in detail below. Formed in the transversestructure 96 is an annular downwardly directed groove 100 spacedinwardly of rib 94 of rim 90. The upper edge of the inner wall 103 ofgroove 100 extends above the upper edge 105 of groove 100 and is slantedor inwardly beveled as shown at 102. The central section of transversestructure 96 is in the form of a disc 104 having an aperture 106therethrough. When one aperture is shown in the drawing, and ispreferred, a plurality may be used having substantially the same radius.Centrally disposed on the upper surface of disc 104 and preferablycoaxial with cap 85 and upwardly extending therefrom is a generallycylindrical post 108. As seen best in FIG. 7, post 108 has a pair ofdiametrically opposed radially outwardly extending arms 110 and 112,respectively, substantially axially coextensive with post 108.Downwardly extending from the bottom surface of disc 104 and radiallyinwardly of aperture 106 are a pair of concentric, annular ribs or beads114 and 116. The inner rib or bead 116 extends downwardly slightly morethan the outer rib or bead 114. The outer rib 114 is disposed in suchradial relation to skirt 86 that upon threading cap 85 on the bottleneck 84, rib 114 will be substantially vertically aligned with the inneredge of the rim of the threaded neck portion 84 of bottle S2, as seenbest in FIG. 6. While two ribs have been found to provide positivesealing in amanner to be described, the number may be varied either toone or more, depending on the material used and results desired. Aboutthe periphery of disc 1 04 there is integrally formed an upstandingcylindrical wall joining disc 104 to the inner wall of groove 100. Wall120 is spaced from the inner surface of skirt 86 to form an annulargroove 122 therewith, concentric with respect to cap 85 and adapted toreceive and hold in a tight, hermetic seal the upper cylindrical rim 124of a diaphragm 126, as best seen Vin FIG. 6. Diaphragm 126 isadvantageously made of a flexible resilient plastic material, such aspolyethylene, and, extending from the lower edge of cylindrical rim 124,has a downwardly, inwardly sloping flexible wall 130, of a generallyfrusto-conical shape surrounding a central aperture 132 therein.Extending downwardly from sloping wall and surrounding aperture 132 arepreferably two downwardly projecting sleeves 134 and 136 providing anannular space therebetween which is adapted to receive and hold theupper end of a pipette or tube 130 in airtight relation. Pipette 138 hasa passage 140 formed therein that extends the full lengthof the tube,which is not shown. Pipette 138 may be of any convenient material suchas glass or synthetic plastic, impervious to the liquid within bottle82.

On the underside of sloping wall 130 of diaphragm 126 are a plurality 0fannular, preferably concentric, downwardly protruding beadsillustratively shown as three, 140, 142 and 144, respectively, which arepreferably positioned to overlie the upper edge of bottle neck 84 forproviding a positive seal upon being urged in contact therewith, asshown best in FIG. 6. While pipette 138 is shovtm as fabricated separatefrom diaphragm 126, these elements may be molded in one piece.

Dropper assembly 80 is completed by aV bulb piece indicated as a wholeby reference character 156, which encloses a spacefabove cap 85 andcontains the metering device. Advantageously, bulb 150 has acomparatively thin, flexible, generally domed, central portion 152 and adepending skirt portion 154. The outer surface of skirt Section 154 hasan outwardly projecting circumferential rib or ange 156 and a downwardlyextending substantionally cylindrical boss E?. Flange 156 iscomplementary to interior groove 92 in rim 90 of cap 85 and boss 158 isreceivable in groove 100 in transverse structure 96 of cap 85, forsecuring the parts together with an airtight seal, as well as providingfor relative rotational movement. As an aid in providing an hermeticseal, the lower inner peripheral edge of skirt portion 154 is beveled at159 to be complementary to beveled surface 102 of transverse structure96. Advantageously, bulb 150 is made of a resilient and pliablematerial, such as polyethylene, rubber or other like material so that,upon being pressed into the concavity of the upper portion of cap 84 thedownwardly extending boss 158 may be yieldably forced into groove 1110and outwardly extending flange 156 yields inwardly and snaps into groove92 in cap 86. Annular bead 94, defining the top of groove 92, aids inrotatably retaining bulb 150 in place and the tight engagement of boss158 by groove 180 and rib 156 into groove 92 and the mating of beveledsurfaces 102 and 159 as shown in FIG. 6 Vforms a tight hermetic sealbetween the bulb and the cap and insures a dependable seal between thoseparts while permitting relative rotation, despite relatively severeexure of bulb 158.

Extending coaxially through the dome portion 152 of bulb 150 andintegral therewith is a plunger 165. Advantageously plunger 165 is rigidand extends upwardly a small extent from the center of the dome portion152 to form an area to which the users linger may be applied to exertcompression pressure on the dropper bulb for customary opera-tion.Plunger 165 extends downwardly into the ,space enclosed by bulb 150 andis of substantially hollow cylindrical shape with a central bore 166substantially axially aligned with post 108 which extends upwardly fromtransverse structure 96 of cap 85. Bore 166 has a diameter substantiallyequal to the outer diameter of post 108 and has a wall thicknesssubstantially equal to the radial extent of each projecting arm 11() and112 of post 108. The wall portion of plunger 165 has a series ofsuccessively descending inverted steps or cutouts extending around onehalf of its circumference, andthe series is repeated with diametralsymmetry for the remaining half-circumference or 180, so that as shownin FIG. 8, each pair of diametrically opposed steps is at the sameheight or axial positionalong the length of the plunger 165. One suchdiametral pair of steps is shown in FIGS. 6 and 9 at 168a and 176a. Thetwo series of steps in the cylindrical wall are of graduated increasingdistance from the lowermost edge 168 of plunger 165 to dome portion 152of bulb 150, so that a line connecting the ends of the steps in eachseries is of helical contour. Illustratively shown iny FIGS. 6 and 9 area first series of eight steps indicated by the reference numerals 168a,170er, 171a, 172a, 173a, 17411, 175a and 176a, respectively. The otherseries of steps is shown in FIG. 8 and is indicated by 168b and 170b to176b, inclusive, with steps or cutouts having like numerals beingEmplementary and of like height.

With bulb 150 in assembled position in cap 84, the lowermost surface 168of plunger 165 is spaced a small distance from the upper surface of arms110 and 112, respectively, as illustrated in FIG. 6. Preferably theupper surfaces of arms 110 and 112, respectively, are each equal to thesurface area of each steps 168 and 1711-176, inclusive, and as shownthese surfaces are in the form of a sector of an annulus. It is apparentthat the relative angular position of plunger 165 with respect to arms111) and 112 about their common axis will determine the ext' tent towhich plunger 165 can be moved downwardly before plunger 165 will bestopped by having one of its step pairs engage arms 110 and 112, andhence the plunger determines how far bulb 150 can be depressed. In theposition shown in FIG. 6, the lowermost surfaces 168g and 168i: ofplunger 165 are disposed opposite arms 110 and 112 so as to allow theVminimum inward movement of plunger 165. In this position there is noeffective downward movement of the dome portion 152 of bulb 156 andhence no drawing in or dispensing of liquid into or from pipette 158.Upon relative rotational movement of cap' 85 and bulb 150, such as 1/16of a revolution of bu1b-150 is the counterclockwise direction, which inthe illustrative case is one step, arms 110 and 112 become verticallyaligned with steps 170a and 17ib, respectively, allowing plunger 165 tobe moved inwardly a predetermined distance equivalent to one step. In asimilar manner, by selected relative rotation of cap and bulb 158,plunger 165 can be depressed inwardly a selected predetermined distance,with the maximum distance occurring when arms 116 and 112 are verticallyaligned with the top steps, here indicated at 17641 and 1765,respectively.- The vertical distance (or rise) between the steps179-176, inclusive, can be selected to be equal Vor varied, as desired,and advantageously as shown in FIGS. 5-9 the vertical distance of eachstep is selected so that for the first step 170, upon depression andrelease of plunger 165 one drop of liquid is drawn into or expelled frompipette 138. For each succeeding step, the step rise or height isdesigned so that one additional drop is thus measured. Thus, in theexample illustrated, any number of drops from O to 7 may be selected bysuitably positioning dome 15) relative to cap 85. It will be understoodthat any desired number of steps and any desired incremental amount ofliquid to be metered may be employed. Asan aid to the user for quicklydetermining the number of drops (or other incremental amount) which maybe drawn into or expelled from pipette 138, the outer surface of domeportion 152 of bulb 150 is provided with a ,pair of numerical scales 179each reading from 0 (or Otf) to 7 about one-half the a respectivestep,lsuch that the numerals 1 are aligned with steps 174m and 17611;numerals 2 are aligned with steps 171e and 171b; and so on, up tonumerals 7 aligned with steps 176g and 176b, as seen` best vin FIG. 8.The notationsA Off are advantageously placed aligned with steps 16811and 16811, respectively.l Arrows or other index marks 182 on oppositesides of the upper, outer peripheral edge of rim of cap 85 and axiallyaligned with arms 118 and 112, cooperate with a series of verticalridges 184 on the outer peripheral surface of skirt portion 154 alignedwith scales 179, as shown best in FIG. 5. Thus marks 182 .cooperate withthe calibrated numerical scale 179 to determine ,the rotational positionof bulb so that the numbers to which arrows 182 point indicate thenumber of drop (or other incremental amounts) which can be drawn intopipette 138 on depression of plunger and can be expelled upon latercornpression.

In assembled position, upon tightening cap 85 upon threaded neck portion84, concentric ribs 114 and 116 on the lower surface of disc 104 areforced downwardly on the flexible, tapered portion 130 of the diaphragm,and hence concentric ribs 140, 142 and 144 on diaphragm 126 are forcedinto sealingV engagement with the upper rim of bottle neck 84, as shownbest in FIG. 6. Since ribs 114 and 116 form a sealing engagement withthe upper surface of sloping section 130 of diaphragm 126, anycommunication between aperture opening 106 in disc 1114 and aperture 132in diaphragm 126, which in turn communicates with opening 14@ of pipette158, is cut olf. Thus, in its closed position on a bottle, dropper 80prevents any dow of liquid from the bottle into the bulb. At the sametime, the seal between diaphragm 126 and the bottle rim completes theclosure for the bottle, and the structure provides a highly effectiveprimary seal.

Upon loosening cap 85 from threaded bottle neck 84, the seal betweendisc 104 and diaphragm 126 is broken, and a passageway is opened fromthe pipette opening 140 through aperture 106 into the space enclosed bybulb 150. Upon rotating bulb 150 relative to cap 85 to the selectednumbered kposition and upon depressing plunger 165 downwardly with thetip of a finger until the plunger cannot be depressed any further due tocontact of the pair of selected steps and arms 110 and 112,respectively, and then upon release of plunger 165, it returns to itsnormal position, and the desired amount of liquid is drawn into opening140 by pipette 138; upon a further depression of plunger 165 to itsmaximum point of depression or until arms 110 and 112 respectivelycontact the steps, the measured amount of liquid in pipette 138 isexpelled therefrom.

While in the description just given, the bulb position was selectedbefore sucking liquid into the pipette, this is not necessary. Forexample, a larger than necessary amount of liquid may be sucked into thepipette; thereafter, the bulb may be set to the desired dose, and upondepressing the bulb, only that dose will be expelled. In this way,successive measured doses may be expelled from the same dropperful ofliquid.

The use of but a single opening 106 between the bulb space and thepipette interior has an added advantage. As is Well known, where anenclosed space has but a single small entrance or exit aperture, liquideither within or outside the space cannot pass through the aperturebecause of the absence of any means for air to exchange place with theliquid. Where the air space within the bulb is smaller than the volumeof the space within the pipette, the single aperture 106 prevents anyliquid from getting into the bulb space, even if the lled dropper shouldbe inverted or placed on its side. It is therefore possible to ll thepipette, and lay the dropper down without either spilling liquid oryhavingit enter the bulb space. In this way, the liquid is kept fromcontact with the bulb itself, and the necessity for carefully selectingliquid impervious materials for the bulb is avoided.

It will be understood that many variations in structure from thoseembodiments described above are possible without deviating from thepresent invention.

Although the skirt portions of the bulbs Were shown to be sealed to theinside surfaces of the caps, they may equally well be sealed to theouter surface of the caps. Further, while the bulbs were shown to havedome shaped portions, any type may be used, such as the conventionalFurther, With slight modification of structure diaphragm 126 andportions of cap 85 may be formed integrally of polyethylene or likematerial, or diaphragm 126 and cap 85 may be of the same or differentmaterials and joined together in any convenient manner forming anairtight seal such as disclosed above.

Though screw threads have been shown for engaging the threads on abottle neck, other means of holding the dropper assembly on a containermouth may of course be used.

While the plunger was shown to have the step sequence and the stopmember the fixed arms, this may be interchanged if desired. Further,while two series of steps were shown, this is not essential and anyconvenient number of step series and of stop arms such as 110, 112 maybe used.' Also, other ways of causing plunger 165 to be 10 rotatedrelative' to stop arms 110 and 112'may be used to avoid any necessity ofrotating bulb in cap 85; for example, plunger may be made rotatablerelative to bulb 150, in which case bulb 150 may be made unitary withcap 85.

A dropper-cap assembly has thus been disclosed for use on threaded orother vessels adapted 'to form a primary seal When fully closed yortightened onto the bottle, to prevent any egress of liquid into the bulbwith consequent possible deterioration of the liquid or of the bulb. Adropper-cap assembly has also been disclosed having a plunger and a stopmember in the path of the compressive movement =of the plunger, with theplunger and stop so interrelated that upon relative rotational movementof them about their axis the plunger travel is selectively limitedthereby to receive and dispense accurately and consistently a selectedamount of liquid.

It will be apparent to those skilled in the art that various otherchanges may be made in the construction of the dropper without departingfrom the spirit and scope of this invention.

What is claimed is:

l. A liquid dropper and closure for a container having a threaded mouthopening comprising a cap member having a depending cylindrical skirtportion provided with screw threads adapted for interengaging with thethreaded mouth of said container, said cap having an upwardly extendingrim, an interior transverse wall projecting from the inner peripheralsurface of said cap and disposed between said downwardly depending skirtportion and upwardly extending rim portion, said upstanding rim havingan interiorly facing groove on its inner peripheral surface spaced abovethe upper surface of said transverse wall, said transverse wall havingan annular groove in its upper surface adjacent the inner peripheralsurface of said rim, a frustro-conical diaphragm of resilient materialhaving an aperture inwardly of its peripheral edge, said diaphragmhaving a rim portion extending upwardly .from the upper surface thereofadjacent its outer peripheral edge, a longitudinally extending tube openat its opposite ends having its longitudinal axis substantially parallelto said cap, means integral with the lower surface of said diaphragm andsurrounding said aperture for retaining said'tube in air-tightcommunication, means integral with the lower surface of said transversewall for retaining said last mentioned upstanding rim in air-tightcommunication, said transverse Wall having an aperture Vpassingtherethrough disposed radially inwardly of said last mentionedupstanding rim, a concentric rib disposed downwardly from the lowersurface of said transverse wall disposed radially inwardly from saidaperture and concentric with said cap, said rib being adapted tosealingly engage the upper surface of saidV diaphragm upon the cap beingthreadedly assembled on the mouth of the container, and a normallyexpanded bulb defining a space above said transverse wall, said bulbincluding a thin-walled outwardly concave dome evertable inwardly forvolume reduction, said bulb having a depending cylindrical skirt portionwith an outwardly projecting circular rib complementary to saidinteriorly facing groove on said rim and having a depending ribcomplementary to said annular groove in the upper surface of saidtransverse wall, both of said ribs fitting in their respective groovesfor providing an air-tight seal between said bulb member and said rimand said transverse wall.

2. A liquid dropper and closure for a container having a threaded mouthopening comprising a cap member having a depending cylindrical skirtportion provided with screw threads adapted for interengaging with thethreaded mouth of said container, said cap having an upwardly extendingrim, an interior transverse wall projecting from the inner peripheralsurface of said cap and disposed between said downwardly depending skirtportion and up- Wardly extending rim portion, said upstanding rim havingan interiorly facing groove on its inner peripheral surface l l spacedabove the upper surface of said transverse wall, said transverse wallhaving an annular groove in its upper surface adjacent the innerperipheral surface of said rim, a longitudinally extending tube open atits opposite ends having its longitudinal axis substantially parallel tosaid cap, said tube having a resilient outwardly ared flexible neckportion on one of its ends, an upstanding rim integrally formed on saidupper surface of the iiared neck portion of said tube, said rim beingradially spaced outwardly from said tube and concentric therewith, meansintegral with the lower surface of said transverse wall for retainingsaid last mentioned upstanding rim in airtight communication, saidtransverse wall having an aperture passing therethrough disposedradially inwardly of said last mentioned upstanding rim, a concentricrib disposed downwardly from the lower surface'of said transverse walldisposed radially inwardly from said aperture kand concentric with saidlongitudinal-tube, said rib being adapted to sealingly engage the uppersurface of said flared neck portion of said tube upon the dropper beingthreadedly assembled on the mouth of the container, and a normallyexpanded bulb delining a space above said transverse wall, said bulbincluding a thin-walled outwardly concave dome evertable inwardly forvolume reduction, said bulb having a depending cylindrical skirt portionwith an outwardly projecting circular rib comple-l mentary to saidinteriorly facing groove on said rim and having a depending ribcomplementary to said annular groove in the upper surface of saidtransverse wall, both of said ribs litting in their respective groovesfor providing an air-tight seal between said bulb member and said rimand said transverse Wall.

3. A liquid dropper and closure assembly for use with a container havingan opening therein, comprising a longitudinally extending tube open yatits opposite ends, a frustro-conical member of resilient material havingan opening therein integrally mounted on one end of the tube having itsopening coaxial thereto, said member having a rim portion extendingradially outwardly Iand substantially transverse to the longitudinalaxis of said tube, said rim portion adapted to overlie the mouth of saidcontainer, an upstanding rim integrally mounted on the upper side ofsaid radially extending surface of said frustro-conical member, said rimbeing concentric to said tube, an interiorly transverse wall integrallyprojecting from the inner peripheral surface of said upstanding rim andspaced from the upper surface of the transverse area of saidfrustroconical member, said annular rim having an interiorly facingmouth of said container whereby communication between said tubeand saidbulb is closed.

` 4. A liquid dropper and closure assembly for a container having anexternally threaded mouth comprising a longitudinally extending tubeopen at its opposite ends, said tube having an outwardly flared flexibleneck portion at one of its end with the area adjacent the peripheraledge of said dared neck portion being substantially transverse to thelongitudinal axis of said tube, said transverse area extending radiallyoutwardly a distance for overlying the upper edge of the mouth of saidcontainer, a downwardly depending rim integrally formed on the neckportion of said tube and having its inner surface threaded forengagement with the threaded mouth of said bottle, a cylindrical capmember mounted on the outer surface of said depending rim, said capextending upwardly beyond the upper surface of the transverse area ofsaid neck portion of said tube, said cap having an interior transversewall intermediate of its ends and spaced from the upper surface of thetransverse area of said neck of said tube, said transverse wall having adepending annular rib being positioned to. substantially overlie theinner edge of the mouth of said container and adapted to engage thetransverse area ot said flared neck portion of said tube along acircular contact line for clamping said neck portion against the rim ofthe mouth of said container upon said depending rim being threadedlyengaged with the mouth of said container, said transverse wall vhavingan aperture therethrough disposed radially between the cylindrical capand said depending rib therefrom, an upwardly domed bulb of resilientmaterial enclosing an airspace between the domed portion of said bulband said transverse wall, said bulb having a depending cylindrical skirtportion tting tightly against the interior surface of said cylindricalbody member, and means hermetically sealing said skirt portion of saidbulb to said'inner surface of said body member.

5. A liquid dropper assembly comprising a tubular body member having aninterior transverse wall, a pipette having its axis substantiallyparallel to the axis of said body member, said kpipette having aresilient outwardly ilared neck portion, means mounted to the undersurface of said transverse wall for retaining said flared neck portionof groove extending entirely around said rim and spaced above saidtransverse wall, an annular rim extending downwardly from saidtransverse wall having its lower surface spaced from said upper surfaceof said frustro-conical member in operative position, said annular ribbeing positioned to engage said upper surface of said frustro-conicalmember along a circular contact line for forcing said frustro-conicalsurface against the mouth of said container upon removably securing saiddropper assembly to the mouth of a container, a compressible bulb memberenclosing the spaceabove said transverse Wall and normally havingmaximum internal volume, said bulb including a thin walled outwardlyconcave spherical dome evertable inwardly for volume reduction andhaving a depending skirt portion fitting tightly against the interiorsurface of said upwardly extending rim and having an outwardlyprojecting circular rib complementary to said inwardly facing groove insaid rim and litting therein to provide an airtight seal between saidbulb and said rim and an aperture passing through said transversewalland disposed radially therein between said downwardly extendingconical rib and said skirt portion of said bulb and means for removablyclamping said rustro-conical member against the upper edge of a mouthofa container by axial pressure applied at the periphery of said rim forforming a positive seal upon said downwardly extending concentric riburging said frustro-conical member into contact with said said pipettein air-tight relation with said transverse Wall, a normally expandedcompressible bulb defining an air space aboveV said transverse wall andbeing in hermetic-sealed relation with said body member and saidtransverse wall, said transverse wall having an aperture therethroughinterconnecting said pipette and the space deiined by said bulb, andmeans for sealing said aperture in response to clamping said bodyVmember against the rim of a bottle neck by an axial force on said bodymember without compressing said bulb.

6. A liquid dropper and cap assembly for a liquidcontaining vesselhaving a mouth, comprising a bulb, a pipette adapted to be inserted intosaid vessel through said mouth, means defining an air-tight passagebetween said bulb and said pipette to provide a dropper assemblytherewith, means cooperating'with said dropper assembly to provide aclosure for said vessel mouth, and means responsive to tightening ofsaid closure upon said vessel without compressing said bulb for blockingsaid passage to isolate the interior of saidbulb from said pipette,whereby a primary closure seal for said vessel is provided.

7. A liquid dropper and cap assembly for use with a liquid-containingvessel having a neck, comprising a closure cap adapted to be placed uponsaid vessel neck to form a closure for said vessel, a pipette, anormally expanded compressible bulb hermetically sealed to said cap,means hermetically sealing said pipette to said cap and including meansdeiining an air passage between said pipette and said bulb, and meansresponsive to tightening of said cap on said vessel neck withoutcompressing said bulb for blocking said passagev to isolate the interiorof said bulb from the interior of said pipette, whereby a primaryclosure seal for said vessel is provided.

8. A liquid dropper closure for a container having a threaded mouthopening comprising a cap member having a depending cylindrical skirtportion provided with screw threads adapted to interengage with thethreaded mouth of said container, said cap having an upwardly extendingrim, an interior transverse wall projecting from the inner peripheral'surface of said cap and disposed between said downwardly dependingskirt portion and -upwardly extending rim portion, said upstanding rimhaving aninteriorly facing groove on its inner peripheral surface spacedabove the upper surface of said transverse wall, said transverse wallhaving an annular groove in its upper surface adjacent the innerperipheral surface of said rim, a longitudinally extending tube open atits opposite ends having its longitudinal axis substantially parallel tosaid cap, said tube having a resilient outwardly dared flexible neckportion on one of its ends, an upstanding rim integrally formed on saidupper surface of the flared neck of said tube, said rim being radiallyspaced outwardly from said tube and concentric therewith, means integralwith the lower surface of said transverse wall for retaining said lastmentioned upstanding rim in air-tight communication, said transversewall having an aperture passing therethrough disposed radially inwardlyof said last mentioned upstanding rim, an annular rib disposeddownwardly from the lower surface of said transverse wall and radiallyinwardly from said aperture and concentric with said longitudinal tube,said rib being adapted to sealingly engage the upper surface of saidflared neck portion of said tube upon the dropper being threadedlyassembled on the mouth of the container, an annular rib extendingdownwardly from the lower surface of said flared neck portion of saidtube being so positioned as to abut the upper edge of the mouth of thecontainer when the closure is disposed thereon, a normally expanded bulbdefining a space above said transverse wall, said bulb including athin-walled outwardly concave spherical dome evertable inwardly forvolume reduction, said bulb having a depending cylindrical skirt portionwith an outwardly projecting circular rib complementary to saidinteriorly facing groove on said rim and having a depending ribcomplementary to said annular groove in the upper surface of saidtransverse wall, both of said ribs fitting in their respective groovesfor providing an air-tight seal between said bulb member and said rimand said transverse wall, said bulb being rotatably movable with respectto said cap, and metering means for predetermining the quantity ofliquid liowing into and out of said tube, said metering means comprisinga stop member extending upwardly from said transverse wall into thespace enclosed by said bulb, said stop member having a pair of outwardlyextending,

diametrically opposed identically shaped arms having' their uppersurfaces coplanar, and a substantially cylindrically shaped plungerdepending from the dome portion of said bulb and axially aligned withsaid stop member and having its lower end surface adjacent the uppersurfaces of said arms of said stop member, said plunger having a seriesof stepped surfaces at preselected distances from said end surface inthe outer wall of said plunger for 180 degrees and repeating said seriesfor the remaining 180 degrees, so that corresponding stepped surfacesare diametrically opposed and lie in the same transverse plane, each ofsaid stepped surfaces being cooperatively shaped to receive said arms ofsaid stop member whereby depending upon the relative position of saidbulb with respect t said cap, said plunger and said stop member being sopositioned and adapted to limit the inward movement of the dome portionof said bulb member thereby allowing the user to eject a preselectedvolume of liquid.

9. A liquid dropper and closure for a container having a threaded mouthopening comprising a cap member having a depending cylindrical skirtportion provided with screw threads adapted for interengaging with thethreade Vmouth of said container, said cap having an upwardly extendingrim, an interior transverse wall projecting from the inner peripheralsurface of said cap and disposed between said downwardly depending skirtportion and upwardly extending rim portion, said upstanding rim havingan interiorly facing groove on its inner peripheral `surface spacedabove the upper surface of said trans- -verse wall, said transverse wallhaving an annular groove in its upper surface adjacent the innerperipheral surface of said rim, a frustro-conical diaphragm of resilientmaterial having an aperture inwardly of its peripheral edge, saiddiaphragm having a rim portion extending upwardly from the upper surfacethereof adjacent its outer peripheral edge, a longitudinally extendingtube open at its opposite ends having its longitudinal axissubstantially parallel to said cap, means integra-l with the lowersurface of said diaphragm and surrounding said aperture for retainingsaid tube in air-tight communication, means integral with the lowersurface of said transverse wall for retaining said last mentionedupstanding rim in air-tight communication, said transverse wall ing aspace above said transverse wall, said bulb including a thin-walledoutwardly concave spherical dome evertable inwardly for volumereduction, said bulb having a depending cylindrical skirt portion withan outwardly projecting circular rib complementary to said interiorlyfacing groove on said rim and having a depending rib complementary tosaid annular groove in the upper surface of said transverse wall, bothof said ribs fitting in their respective grooves for providing anairtight seal between said bulb member and said rim and said transversewall, a generally tubular plunger having one end coupled to the innersurface of said bulb for axially moving its other end towards saidtransverse wall `upon axial compression of said bulb, said plungerhaving a series of stepped surfaces in its wall at predetermineddistances from its said other end, a stop member iixedly mounted on theupper surface of said transverse wall in coaxial relationship to saidplunger, said stop member having a shank extending outwardly from saidtransverse wall and adapted to extend slidably into the bore of saidtubular plunger, and an arm extending radially outwardly from said shankand having an upper surface in opposed spaced axial relationship withsaid other end of said plunger upon said bulb being expanded and saidsurface being shaped to cooperatively coact with said stepped surfaces,said bulb being turnable about its axis for disposing a selected steppedsurface of said plunger in axially opposed spaced relation to said arm,hleieby selectively varying the inward movement of said l0. A liquiddropper and closure for a container having a threaded mouth openingcomprising a cap member having a dependent cylindrical skirt portionprovided with screw threads adapted for interengaging with the threadedmouth of said container, said cap having an upwardly extending rim, aninterior transverse wall pro- ]ectmg from the inner peripheral surfaceof said cap and disposed between said downwardly depending skirt portionand upwardly extending rim portion, said upstanding rim having aninteriorly facing groove on its inner peripheral surface spaced abovethe upper surface of Asaid transverse wall, said transverse wall havingan annular groove in its upper surface adjacent the inner peripheralsurface of said rim, a frustro-conical diaareas-ea vphragm of resilientmaterial having an aperture inwardly of its peripheral edge, saiddiaphragm having a rim portion extending upwardly from the upper surfacethereof adjacent its outer peripheral edge, a longitudinally extendingtube open at its opposite ends having its longitudinal axissubstantially parallel to said cap, means integral with the lowersurface of said diaphragm and surrounding said aperture for retainingsaid tube in airtight communication, means integral with the lowersurface of said transverse Wall for retaining said last mentionedupstanding rim in air-tight communication, said transverse Wall havingan aperture passing therethrough face of said diaphragm upon the capbeing threadedly assembled on the mouth of the container, a normallyexpanded bulb defining a space above said transverse Wall, said bulbincluding a thin-walled outwardly concave spherical dome evertableinwardly for volume reduction, said bulb having a depending cylindricalskirt portion with an outwardly projecting circular rib complementary tosaid interiorly facing groove on said rim and having a depending ribcomplementary to said annular groove in the upper surface of saidtransverse wall, both of said ribs fitting in their respective groovesfor providing an air-tight seal between said bulb member and said rimand said transverse Wall, a plunger fixed to said bulb for axialmovement inwardly toward said transverse Wall upon compression of saidbulb, said plunger having a series of sequential stepped surfacestherein of dierent distances from said transverse Wall, and acooperating member fixed on the upper surface of said transverse wallcoaxially to said plunger and having stop means thereon for cooperativeengagement with selected ones of said stepped surfaces of said plungerfor selectively limiting the inward movement of said bulb.

11. YA liquid dropper and closure assembly for a container having anexternally threaded mouth comprising a longitudinally extending tubeopen at its opposite ends, said tube having an outwardly flared flexibleneck portion at one of its ends with the area adjacent the peripheraledge of said liared neck portion being substantially transverse to thelongitudinal axis of said tube, said transverse area extending radiallyoutwardly a distance for overlying the upper edge of the mouth of saidcontainer, a downwardly depending rim integrally formed on the neckportion of said pipette and having its inner surface threaded forengagement with the threaded mouth of said bottle, a cylindrical capmember mounted on the outer surface of said depending rim, said capextending upwardly beyond the upper surface of the transverse area ofsaid neck portionof said tube, said cap having an interior transverseWall intermediate of its ends and spaced from the upper surface of thetransverse area of said neck of said tube, said transversewall having adepending annular rib being positioned to substantially overlie theinner edge of the mouth of said container and adapted to engage thetransverse area of said fiared neck portion of said tube along acircular contact line for clamping said neck portion against the rim ofthe mouth of said container upon said depending rim being threadedlyengaged with the mouth of said container, said transverse wall having anaperture therethrough disposed radially between the cylindrical cap andsaid depending rib therefrom, an upwardly domed bulb of resilientmaterial enclosing an air space between the domed portion of said bulband said transverse wall, said bulb having a depending cylindrical skirtportion fitting tightly against the interior surface of said cylindricalbody member, means hermetically sealing said skirt portion of said bulbto said inner surface of said body member, a generally tubular kplungerhaving one end coupled to the inner surface of said bulb l@ for axiallymoving its other end towards said transverse Wall upon axial compressionof said bulb, said plunger having a series of stepped surfaces in itswall at predetermined distance from its said other end, a stop memberxedly mounted on the upper surface of said transverse wall in coaxialrelationship to said plunger, said stop member having a shank extendingoutwardly from said transverse wall and adapted to extend slidably intothe bore of said tubular plunger, and an arm extending radiallyoutwardly from said shank and having an upper surface in opposed spacedaxial relationship with said other end of said plunger upon said bulbbeing expanded and said surface being shaped to cooperatively coact withsaid stepped surfaces, said bulb being turnable about its axis fordisposing a selected' stepped surface` of said plunger in axiallyopposed spaced relation to said arm, thereby selectively varying theinward movement of said bulb.

12. A liquid dropper and closure assembly for a container having anexternally threaded mouth comprising a longitudinally extending tubeopen at its opposite ends, said tube having an outwardly flared flexibleneck portion at one of its ends with the area adjacent theperiph eraledge of said flared neck portion being substantially transverse to thelongitudinal axis of said tube, said transverse area extending radiallyoutwardly a distance for overlying upper edge of the mouth of saidcontainer, a downwardly depending rim integrally formed on the neckportion of said pipette and having kits inner surface threaded forengagement with the threaded mouth of said bottle, a cylindrical capmember mounted on the outer surface of said depending rim, said capextending upwardly beyond the upper surface of the transverse area ofsaid neck portion of said tube,l said cap having an interior transversewall intermediate of its ends and spaced from the upper surface of thetransverse area of said neck of said tube, said transverse wall having adepending annular rib being positioned to substantially overlie theinner edge of the mouth of said container and adapted to engage thetransverse area of said flared neck portion of lsaid tube along acircular contact line for clamping said neck portion againstV the rim ofthe mouth of said container upon said depending rim being threadedlyengaged with the mouth of said container, said transverse wall having anaperture therethrough disposed radially between the cylindrical cap andsaid depending rib therefrom, an upwardly domed bulb of resilientmaterial enclosing an air space between the domed portion of said bulband said transverse wall, said bulb having a depending cylindrical skirtportion fitting tightly against the interior surface of said cylindricalbody member, means hermetically sealing said skirt portion of said bulbto said inner surface of said body member, a plunger fixed to said bulbfor axial movement inwardly towards said transverse Wall uponcompression of said bulb, said plunger having a series of sequentialstepped surfaces thereon of diferentdistances from said transverse wall,and a cooperating member xed on the upper surface of said transversewall coaxially to said plunger and having stop means thereon for`cooperative engagement with selected ones of said stepped surfaces ofsaid plunger for selectively limiting the inward movement of said bulb.

13. A liquid dropper assembly comprising a tubular body member having aninterior transverse wall, an elongated tube having a longitudinalopening therein, means mounting said tube with its longitudinal axisaligned substantially parallel to the axis of said body member on theunder surface of said transverse wall in air-tight relation therewith, anormally expanded compressible bulb having a resilient continuous Walldefining an air space above said transverse wall and being inhermetic-sealed relation with said body member and said transverse wall,said transverse wall having an aperture therethrough olfset from itsaxis for interconnecting said opening in said tube and the space definedby said bulb, a generally tubular plunger having one end coupled to theinner surface of said bulb for axially moving its other end towards saidtransverse wall upon axial compression of said bulb, said plunger havinga series of stepped surfaces in its wall at predetermined distances fromsaid other end, a stop member xedly mounted on the upper surface of saidtransverse wall in coaxial relationship to said tubular body member andsaid plunger, said stop member having a shank extending outwardly fromsaid transverse wall and adapted to extend slidably into the bore ofsaid tubular plunger and an arm extending radially outwardly from saidshank and having an upper surface in opposed spaced axial relationshipwith said other end of said plunger upon said bulb being expanded andsaid surface being shaped to cooperatively coact with said steppedsurfaces, said bulb being turnable about its axis for disposing aselected stepped surface of said plunger in axially opposed spacedrelation to said arm, thereby selectively varying the inward movement ofsaid bulb.

14. A liquid dropper assembly comprising a tubular body member having aninterior transverse wall, an elongated tube having a longitudinalopening therein, means mounting said tube with its longitudinal axisaligned substantially parallel to the axis of said body member on theunder surface of said transverse wall in air-tight relation therewith, anormally expanded compressible bulb defining an air space above saidtransverse wall and being in hermetic-sealed relation with said bodymember and said transverse wall, said transverse wall having an aperturetherethrough for interconnecting said opening in said tube and the spacedefined by said bulb, said bulb being rotatably movable with respect tosaid body member, and metering means for predetermining the quantity ofliquid fiowing into and out of said tube, said metering means comprisinga stop member extending upwardly from said transverse wall into thespace enclosed by said bulb, said stop member having a pair of outwardlyextending, diametrically opposed identically shaped arms having theirupper surfaces coplanar, and a substantially cylindrically shapedplunger depending from the dome portion of said bulb and axially alignedwith said stop member and having its lower end surface adjacent theupper surfaces of said arms of said stop member, said plunger having aseries of stepped surfaces at preselected distances from said endsurface in the outer wall of said plunger for 180 degreesV and repeatingsaid series for the remaining 180 degrees, so that corresponding steppedsurfaces are diametrically opposed and lie in the same transverse plane,each of said stepped surfaces being cooperatively shaped to receive saidarms of said stop member whereby depending upon the relative position ofsaid bulb with respect to said cap, said plunger and said stop memberbeing so positioned and adapted to limit the inward movement of the domeportion of said bulb member thereby allowing the user to eject apreselected volume of liquid.

15. A liquid dropper assembly comprising a tubular body member having aninterior transverse wall, a pipette having its axis substantiallyparallel to the axis of said body member, means secured to the undersurface of said transverse wall for retaining said pipette in air-tightrelation therewith, a normally expanded compressible bulb defining anair space above said transverse wall and being in hermetic-sealedrelation with said body member and said transverse wall, said transversewall having an aperture therethrough offset from its axis forinterconnecting said pipette and the space defined by said bulb, meansfor closing said aperture in response to clamping of said body memberagainst the rim of a bottle neck by an axial force on said body member,said bulb having a resilient continuous dome portion adapted for axialmovement inwardly towards said transverse wall, a plunger lixed to saiddome portion and extending inwardly into the space defined by said bulband axially movable in unison with said dome portion, said plungerhaving a series of sequential stepped surfaces thereon of differingdistances from 18 said transverse wall and a cooperating memberextending upwardly from said transverse wall and coaxially to said bodymember and said plunger and having stop means for cooperative engagementwith selected stepped surfaces of said plunger for selectively limitingthe inward movement of said dome portion of said bulb.

16. A liquid dropper assembly comprising a tubular body member having aninterior transverse wall, an elongated tube having a longitudinalopening therein, means mounting said tube with its longitudinal axisaligned substantially parallel to the axis of said body member on theunder surface of said transverse wall in air-tight relation therewith, anormally expanded compressible bulb having a resilient continuous walldefining an air space above said transverse wall and being inhermetic-sealed relation with said body member and said transverse wall,said transverse wall having an aperture therethrough for interconnectingsaid opening in said tube and the space defined by said bulb, a plungerfixed to said bulb for axial movement inwardly towards said transversewall upon compression of said bulb, said plunger having a series ofsequential stepped surfaces thereon of different distances from saidtransverse wall, and a cooperating member fixed on the upper surface ofsaid transverse wall coaxially to said body member and said plunger andhaving stop means thereon for cooperative engagement with selected onesof said stepped surfaces of said plunger for selectively limiting theinward movement of said bulb.

17. A liquid dropper assembly comprising an elongated tube having alongitudinal opening therein and open at both ends, a normally expandedcontinuous resilient bulb having an opening therein at one end anddefining an air space above one end of said tube, said openings in saidtube and said bulb being axially aligned, means for holding said bulband said tube in hermetic-sealed relation,

said bulb having an interior transverse wall adjacent said openingtherein and above said one opening of said tube, said transverse wallhaving an aperture therethrough for interconnecting said tube openingand the space defined by said bulb, a plunger fixed to said bulb foraxial movement inwardly towards said transverse wall upon compression ofsaid bulb, said plunger having a series of sequential stepped surfacesthereon of differentdistances from said transverse wall, and acooperating member fixed on the upper surface of said transverse wallcoaxially to Said tube and said plunger and having stop means thereonfor cooperative engagement with selected ones of said stepped surfacesof said plunger for selectively limiting the inward movement of saidbulb.

18. A liquid dropper and cap assembly for use with a liquid-containingvessel having a neck comprising a closure cap adapted to be placed uponsaid vessel neck to form a closure for said vessel, a pipette, anormally expanded compressible bulb hermetically sealed to said cap,means hermetically sealing said pipette to said cap and including meansdefining an air passage between said pipette and said bulb, meansresponsive to tightening of Said cap on said vessel neck for blockingsaid passage to isolate the interior of said bulb from the interior ofsaid pipette, whereby a primary closure seal for said vessel isprovided, means mounted on said bulb and said cap for adjustablylimiting the compression of said bulb, whereby the change in volume ofsaid bulb may be adapted to correspond to desired amounts of liquid tobe dispensed.

19. Adjustable liquid drop dispensing apparatus comprising a bulb memberhaving a resilient continuous portion, a body member hermetically sealedto said bulb member, and means mounted on each of said members foradjustably limiting the movement of said bulb movable portion, said lastmentioned means including a plunger having an end and a series ofsequential stepped surfaces thereon of different distances from saidend, and a stop member coaxial to said body member and said plungerhaving means thereon for cooperative engagement with selected steppedsurfaces of said plunger for selectively limiting the movement of saidbulb.

20. A liquid dropper and cap assembly for a liquid containing vesselhaving a mouth, comprising'a bulb member having a movable portion, apipette adapted to be inserted intosaid vessel through said mouth, meansdefining an airtight passage between said bulb and said pipette toprovide a dropper assembly therewith, means cooperating with saidassembly to provide a closure for said vessel mouth, means responsive totightening of said closure upon said vessel for blocking said passage toisolate the interior of said bulb from said pipette, whereby a primaryclosure seal for said vessel is provided, and means mounted on said bulband said assembly for adjustably limiting the movement of said bulbmovable portion whereby the change in volume of said bulb may be ad#justed to correspond to desired amounts of liquid to be dispensed.

21. A liquid dropper and cap assembly for use with the liquid containingvessel having a neck, comprising a closure cap adapted to be placed uponsaid vessel neck to form a closurefor `said vessel, a pipette, anormally expanded compressible bulb hermetically sealed to said cap,means hermetically sealing said pipette to said cap and including meansdefining an air passage between said pipette and said bulb, meansresponsive to tightening of said cap on said vessel neck forblocking'said passage to isolate the interior of said bulb from theinterior of said pipette, whereby a primary closure seal for said vesselis provided, and firstand second cooperable stop members carriedrespectively by said bulb and said cap for limiting the advance of saidbulb, one of said stop members having an end surface with portions ofdiffering distance with respect to said other stop member andindividually and selectively engageable with said other said stop memberfor adjustably determining the movement of said bulb.

22. A liquid dropper and cap assembly for a liquid containing vesselhaving a mouth, comprising a bulb member having a movable portion, apipette adapted to be inserted into said vessel through said mouth,means defining an airtight passage between said bulb and said pipette'to provide a dropper assembly therewith, means cooperating with 'saidassembly to provide a closure for said Vessel mouth, means responsive totightening of said closure on said vessel for blocking said passage toisolate the interior of said bulb from said pipette, whereby a primaryclosure seal for said vessel is provided, and means mounted on said bulbkand said assembly for adjustably limiting the movement of said bulbmovable portion, said last mentioned means including a plunger havinganend and a series of sequential stepped surfaces thereon of differentdistances from said end, and a stop member coaxial to said plungerhaving means thereon for a cooperative engagement with selected steppedsurfaces of said plunger vfor selectively limiting the movement of saidbulb.

23. A liquid dropper and cap assembly for use with a liquid` containingvessel having a neck, comprising a sealed bulb member having a movableportion, a closure cap adapted to be placed upon said vessel neck toform a closure for said Vessel, said cap being hermetically sealed tosaid bulb member, a pipette hermetically'sealed to said cap, meansdefining an air passage between said pipette and said bulb member andmeans responsive to tightening of said closure cap upon said vessel neckfor blocking said passage to isolate the interior of said bulb memberfrom the interior of said pipette tube, said passage blocking meanscomprising a transverse wall on said cap and an annular rib projectingfrom the under surface of said Wall, said air passage being radiallyoutward of said annular rib, and said assembly including meanscooperating with said vessel neck and said rib to block said passage.

24. A metering device comprising a first piece having a peripheral walland with an opening at one end, a second piece mounted on said firstpiece and having a resilient continuous wall and completely closing andsealing said opening, means mounted on each of said pieces foradjustably limiting the movement of said resilient wall whereby thechange in volume of said resilient wall may be adjusted to correspond todesired amounts of liquid to be dispensed, said means including a firstmember having an end and a series of sequential stepped surfaces thereonof different distances from said end, and a stop member mountedcoaxially with respect to said peripheral wall and positioned and shapedto receive said first member and having means thereon for cooperativeengagement with a selected stepped surface of said first member forselectively limiting movement of said resilient wall.

25. A metering liquid dropper assembly comprising a first piece having aperipheral Wall and with an opening at one end, and a second piecerotatably mounted on said first piece and having a resilient continuousWall completely enclosing and sealing said opening, one of said pieceshaving a plunger mounted thereon, the other of said pieces having aguide member mounted coaxially With respect to said peripheral Wall andpositioned and shaped to receive said plunger, said plunger and guidemember being axially slidable relative to one another upon deiiection ofsaid resilient wall, said plunger having an 'end and a series ofsequential stepped surfaces thereon of diiferent distances from saidend, said guide member including stop means for cooperative engagementwith selected stepped surfaces of said plunger for different relativerotational positions of said pieces.

References Cited in the file of this patent UNITED STATES PATENTS 2, 3 11,3 67

6. A LIQUID DROPPER AND CAP ASSEMBLY FOR A LIQUIDCONTAINING VESSELHAVING A MOUTH, COMPRISING A BULB, A PIPETTE ADAPTED TO BE INSERTED INTOSAID VESSEL THROUGH SAID MOUTH, MEANS DEFINING AN AIR-TIGHT PASSAGEBETWEEN SAID BULB AND SAID PIPETTE TO PROVIDE A DROPPER ASSEMBLYTHEREWITH, MEANS COOPERATING WITH SAID DROPPER ASSEMBLY TO PROVIDE ACLOSURE FOR SAID VESSEL MOUTH, AND MEANS RESPONSIVE TO TIGHTENING OFSAID CLOSURE UPON SAID VESSEL WITHOUT COMPRESSING SAID BULB FOR BLOCKINGSAID PASSAGE TO ISOLATE THE INTERIOR OF SAID BULB FROM SAID PIPETTE,WHEREBY A PRIMARY CLOSURE SEAL FOR SAID VESSEL IS PROVIDED.